At present, carrier aggregation is adopted in a Long Term Evolution-Advanced (LTE-A) system. Carrier aggregation refers to inclusion of a plurality of component carriers respectively in the uplink and the downlink in a cell instead of the pattern with inclusion of only one set of carriers in Long Term Evolution (LTE) and earlier wireless communication systems (that is, one uplink carrier and one downlink carrier). For example, some frequency spectrums allocated to the existing systems are aggregated into a large bandwidth for provision to the LTE-A system for use, and at this time the uplink carriers and the downlink carriers in the system can be configured asymmetrically, that is, a UE may occupy N downlink carriers for downlink transmission and M uplink carriers for uplink transmission, where N≠M, as illustrated in FIG. 1A.
Existing aggregation for a User Equipment (UE) takes place in a Frequency Division Duplex (FDD) cell or a symmetric TDD cell. Taking a 2.6 GHz frequency spectrum as an example, there is a currently available TDD and FDD frequency spectrum use scheme as illustrated in FIG. 1B:
Particularly there are two segments of guard bandwidths G1 and G2 reserved between TDD and FDD frequency spectrums so as to avoid interference between them.
In order to improve the efficiency of using the TDD frequency spectrum, it is desirable to be able to make use of these two guard bandwidths G1 and G2 to thereby constitute an asymmetric TDD cell.
In the existing systems, the UE can only operate on an FDD cell or a symmetric TDD cell. However for the LTE-A system, an asymmetric TDD cell may be active for an improved efficiency of using the TDD frequency spectrum. A solution to operation of a UE on an asymmetric TDD cell has been absent so far.